Major service components encompass complete assemblies and substantial sub-systems requiring complex installation and calibration. These parts generally include engine internals, complete drivetrain assemblies, and full chassis/suspension overhauls. Technical features often involve precision machining, specialized materials for high stress/temperature applications, and integrated electronic control interfaces. Proper function relies on adherence to torque specifications, correct timing procedures, and diagnostic scan tool operation post-installation. Replacement typically necessitates removal of multiple surrounding components and often requires specialized tools for disassembly and reassembly. These parts are utilized across all vehicle makes and models, though specific design varies significantly.